Naughty Naughty is an achievement in Halo 3: ODST and Halo: The Master Chief Collection. It is awarded for killing 10 Engineers in New Mombasa at night, alone or with another ODST. It is worth 5 Gamerpoints in ODST and 10 in The Master Chief Collection.
- If one stumbles upon a group of Covenant forces being shielded by an Engineer and do not wish to give away ones' position by trying to kill the Engineer first, killing the squad the Engineer is shielding will cause it to self-destruct. As long as the player has attacked the Engineer sometime during the attack, the player will get credit for killing it.
- To conserve ammo, one can look for the Engineers that are isolated from other Covenant troops in the garden areas in the level Mombasa Streets. Even though these Engineers will provide energy shielding for each other, one charged Plasma Pistol shot can kill an Engineer on Normal difficulty.